What is the normal thickness of NT?

The Nt test is one of many prenatal check-up items, mainly referring to the nuchal translucency. It is mainly used to check whether the baby is developing well and whether there will be Down syndrome, so it is very important for the family. Generally, the thickness of the baby's nuchal translucency often reflects the baby's health. The thicker the nuchal translucency, the worse the baby's health. So what is the normal thickness of the NT examination?

First, let’s talk about what the NT test is. NT refers to the baby's nuchal translucency. Before the baby's lymphatic system is fully developed, a small amount of lymph fluid will accumulate in the neck to form a transparent layer, which is the NT. The NT examination is to measure the thickness of the fetal nuchal translucency through B-ultrasound to infer whether the fetus has congenital abnormalities. Clinical data show that among fetuses with thickened NT, a small number will have chromosomal abnormalities, the most common of which is Down syndrome. In addition, the risk of congenital heart disease, malformations and other diseases will increase accordingly if NT thickens.

Generally speaking, in NT examination, the thicker the thickness, the worse it is. Clinically, a NT thickness of less than 2.5 mm is considered normal. But a thickened NT does not mean that the baby will definitely have Down syndrome! A thickened NT is only a screening method, which means that the baby’s risk of abnormalities is higher than the average person. For babies with thickened NT, most of the time it is just a false alarm and further examination does not reveal any abnormalities. As a pregnant mother who believes that "women are weak in nature but strong as mothers", your attitude towards the NT examination should be: "don't be anxious, don't ignore it." If the doctor tells you that your baby's NT is thickened, you must listen carefully to the doctor's explanation and cooperate with the doctor for further examination.

Now that we know what the NT test is, the next step is to know when to do this test. The NT test is usually completed through B-ultrasound between 11 weeks and 13 weeks + 6 days of pregnancy. At this time, the fetal head-to-rump length is approximately between 45 and 84 mm, and the data can be measured through B-ultrasound. At this time point, obstetricians generally remind pregnant mothers to remember it, because:

During 10 to 13 weeks of pregnancy, 98% to 100% of the NT thickness can be measured, while at 14 weeks of pregnancy this drops to 11%. Why? The reason is that before 11 weeks of pregnancy, the baby is too small and scanning is technically difficult; and after 14 weeks of pregnancy, excess fluid may be absorbed by the baby's developing lymphatic system, and the measurement results will become increasingly inaccurate.

In addition, we also recommend that pregnant mothers undergo NT examination before 13 weeks of pregnancy. Because when measuring NT, the doctor needs to change the pregnant mother's body position or change the position of the probe to find the most suitable posture to obtain the most accurate examination results. Sometimes, the baby in the belly is not cooperative and cannot get into the right position. The pregnant mother needs to take a walk first and then test again after the baby changes his position. If by chance you fail to achieve the right position after trying several times, then the pregnant mother can only make an appointment for the next check-up. Therefore, in order to avoid this situation, it is best for pregnant mothers to do it in advance. In case the test fails, they can test it again.

Having said so much, do you have a clearer understanding of NT examination? Next, let's highlight the key points. Pregnant mothers who can't remember all the content can just remember these points!

The NT test is mainly used to check whether the fetus has congenital abnormalities, and is mainly used to screen for Down syndrome.

The time for NT examination is between 11 weeks of pregnancy and 13 weeks + 6 days of pregnancy. It is best to do the examination before 13 weeks of pregnancy.

The thicker the NT, the greater the risk of fetal abnormalities. NT greater than or equal to 2.5 mm is considered NT thickening.

What is NT test?

Answer: During the 11th to 14th week of pregnancy, pregnant mothers usually have to undergo a special color ultrasound examination - NT color ultrasound.

NT is the abbreviation of nuchal translucency, which refers to the "neck translucency", which is the maximum thickness between the skin and subcutaneous soft tissue on the horizontal sagittal surface of the fetal cervical spine.

The NT test is also one of the diagnostic bases for early Down syndrome screening. The purpose of the test is to diagnose chromosomal diseases and detect fetal abnormalities caused by various reasons at an earlier stage of pregnancy.

Pregnant mothers generally do not need to make too much preparation when doing NT examination, and do not need to fast or hold urine.

What is the normal range of NT value?

NT value ≤ 2.5 mm, normal;

NT value >2.5 mm, abnormal.

If the thickness of the nuchal translucency exceeds 2.5 mm, the larger the NT value, the higher the probability of fetal chromosomal abnormalities.

For pregnant mothers in this situation, doctors will recommend chorionic villus sampling or amniocentesis to determine whether the fetus has chromosomal abnormalities.